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How Cancer Registries Work

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Have you ever wondered, "How do we know what causes cancer?" or "Who is most likely to get cancer and why?" Cancer registries help answer these important questions.

What Is a Cancer Registry?

A cancer registry collects detailed information about cancer patients and the treatments they receive, and stores it in a computer. They can then search this information to answer questions like:

Are more or fewer people getting colon cancer this year compared to last year?

Is there a certain area of the state where women are finding out they have breast cancer at a late stage, when it's harder to treat?

What groups of people are most likely to get skin cancer?

The cancer registry shares the answers to these questions with other groups like the state comprehensive cancer control coalition, which try to find out what can be done. They may find that some people aren't getting the cancer screening tests they need, or they're doing things that make them more likely to get cancer, or something in their home or workplace is causing cancer. The groups try to fix the problem, and the cancer registry gives them new information so they know if their solution works.

Examples of Cancer Registries in Action

Alaska: Do Rocks Cause Lung Cancer?

In Alaska, some rocks contain asbestos, a mineral that can cause lung cancer. Some of these asbestos-containing rocks are used to build roads and airport runways. Scientists were doing research to find out if people got lung cancer from the rocks.

The U.S. Geological Survey provided a map showing where the most asbestos-containing rocks are located. The Alaska Cancer Registry made a map of where people who have lung cancer live. When the two maps were compared, they found out that there is no link between the locations of the asbestos-containing rocks and where people who have lung cancer live. So it's unlikely that people are getting lung cancer from rocks.

Kentucky: Fighting Colorectal Cancer Successfully

The Kentucky Cancer Registry found out that colorectal cancer rates were increasing in the state, and that only about one-third of people who should have been screened for colorectal cancer really had been screened.

The Kentucky Cancer Consortium and the Kentucky Cancer Program used this information to help get more people screened for colorectal cancer. The percentage of Kentuckians who were screened rose from about 35% in 1999 to about 64% in 2008.

California: Dramatic Increase in Colorectal Cancer Among Koreans

The California Cancer Registry looked at trends in colorectal cancer among six major Asian subgroups: Chinese, Japanese, Filipinos, South Asians, Vietnamese, and Koreans. Colorectal cancer was increasing among Koreans, unlike the other five groups.

The registry shared this information with the California Colorectal Cancer Coalition, which is working on a plan to educate Korean communities in California about colorectal cancer screening.

How Cancer Registries Work

To explain how registries work, we'll use a simple example.

Jennifer, a 55-year-old secretary, gets a routine mammogram, which shows she has a tumor about the size of a large pea in her left breast. Jennifer gets an operation at a hospital to remove the tumor, and afterward she gets chemotherapy treatments to make sure the cancer is all gone.

Before the operation, Jennifer gave the hospital some information about herself, including her name, address, age, race and ethnicity, and health insurance company. Jennifer's doctors wrote down information about the tumor, like where it was located and how big it was, and what they did to treat it.

The hospital has its own cancer registry. A specially trained person called a cancer registrar looks at Jennifer's medical record and puts the information about her, her cancer, and her treatment into a computer using special codes. The cancer registrar also makes sure no important information is missing; if it is, he or she asks Jennifer's doctors or other hospital staff for the information. Once a year, the hospital registry sends this information to the central cancer registry in its state.

The state central cancer registry does its best to get information about every cancer case in the state. It reviews the information to make sure it's right and that no information is missing. Once a year, most state central cancer registries send information to CDC's National Program of Cancer Registries (NPCR), and some state and city cancer registries send information to the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program. The central cancer registries don't send any information that could identify a specific patient, like his or her name, street address, or Social Security number. The NPCR and SEER check the information again, and then the information is published every year in the United States Cancer Statistics: Incidence and Mortality Web-based Report (USCS).

How USCS Data Are Used

Scientists all over the world use USCS data in studies about cancer. Here are some examples of research by CDC scientists that used USCS data:

Cancer Incidence in American Indians and Alaska Natives: These reports found that American Indians and Alaska Natives are more likely than non-Hispanic white people to get cancers of the kidney, stomach, cervix uteri, liver, and gallbladder, and less likely to get other kinds of cancer.